Abstract: To study the effects of high-fluoirde and low-iodine DNA damage in the lung of old rats. The experimental models were set up by treating Wistar albino rats with water fluoride (100 mg/L NaF), diet from the area of low iodine (0.0855 mg/kg), or both water fluoride and low iodine respectively. The samples of lung were obtained by rats’ decapitation at 20 months old and were made into unicellular liquid respectively for SCGE. In comparison with DNA damage in the lung cells of the control group 1(58.46%±12.21%), such DNA damage in the HiF, LI, and HiF+LI groups 2, 3 and 4, was 75.55%±7.69%, 87.55%±12.89% and 99.37%±1.76%, respectively. Moreover, the proportion of grade III lung cells damage increased by 70.00% in group 2, 40.62% in group 3, and 79.31% in group 4, as compared to the control group 1. These findings indicated that excessive long-term intake of fluoride, with or without adequate I intake, was a significant risk factor for the development of lung damage.

Key words: high-fluoirde and iodine deficiency; old rats; lung; DNA damage